Let's just say it up-front: the name is the least good thing about this otherwise impressive new restaurant. "It sounds like somewhere you wouldn't want to let the dog off the leash," said one wag. "Not somewhere you'd walk in an open-toed shoe," said another. The logotype - an inky, smeary, Ralph Steadman-esque rendering of the words "Gastro Park", with a stained-looking swing hanging from the A and the S - doesn't help. It wouldn't be out of place on a Hunter S Thompson book jacket or a Korn album cover. But on a menu? Maybe we can all just start calling it The Park, and be done with it. Good to get it out of the way, at any rate, because this is a restaurant that you're going to want to talk about a lot.

Owner and chef Grant King is so busy sawing open tuna spines, liquefying gnocchi and doing faintly magical things with fish scales that he probably doesn't really mind what you think of the name, let alone the fonts. Having wowed Sydney with his cooking over the years with Greg Doyle at Pier, he now finds himself in a restaurant stripped of the trimmings, with the focus squarely on the people and the table: no cloths, no show plates. The menus are A4 laser-prints, and there's a welcome absence of white gloves. This is the site that was briefly home to Blanco (so briefly, in fact, it's almost new), renovated with a will and a way and an eye on the overdraft rather than a fat budget. Rose Bay used to be the view; now it's the flotsam and jetsam of Kings Cross. Gawk too long and you might be lucky enough to get an unhinged tirade directed at you through the glass. Ours ended in "you're dead, all of you". The city council's banners flutter from the lamp-posts: "Been drinking? Walk safe." More wine, sir?

But wait. Liquid gnocchi? Tuna spines? Are alarm bells ringing already? Well they might. This is no restaurant designed by committee. It's abundantly clear that no one has tested the typefaces on the menu with a focus-group or chosen the cuisine to best exploit the latest trend or a gap in the market. This is not a restaurant for everyone, and it certainly doesn't aim to please all comers. It's not arrogance, it's just that King is intent on pushing the boat out here, and boy, has he given it a good shove. He's a chef clearly captivated by the magics of the great wizards of Spanish gastronomy, but his years as head chef with Greg Doyle at Pier have also driven a respect for raw product of the very finest quality deep into the grain of who he is and how he cooks.

Restaurant-goers more besotted with the leafy foragings of the Noma-led new-Scandinavian style of food might find the wealth of smeared and swirled purées on the plate and multiple uses of the phrase "textures of [insert ingredient here]" on the carte dated, tropes of a technique and an aesthetic that is now past its use-by date. Others may simply find it too busy, too worked, or even too precious. ("Rhubarb wire? Rhubarb wire?" as a friend put it. "What the hell?") What you can't argue with is the quality of the food on the plate. Gently run your fork along the block of confit blue eye, and watch as it falls away in firm, fat, silky flakes. Spear it up with some near see-through panes of spicy chorizo, a sliver of octopus and a strand of artichoke stem. There's a tickle of salty preserved lemon in there, and a couple of crinkled blades of cavolo nero. The play of textures is sublime, the mingling of flavours sure, and everything is cooked just so.

So while King makes no apologies about wanting to experiment, about his technique-heavy cooking, about keeping the Park playful, and changing the menu as his whim and his produce dictates, his key concession to you, the customer, is that he goes a long way out of his way to make sure what's on the plate tastes as good as it can taste. He is very good at his job. Raw kingfish, under its crown of hot and sharp Thai flavours, is cut with sashimi-expert precision. The rich dark flavours of pressed lamb rib flaps melt into their cauliflower plate-mate. Even in a side dish, potato churros squirm from their bowl like Chihuly works rendered in crisp, golden carbs.

Then there are the fish scales. King has adapted a technique he saw deployed at Martín Beratsagui in Spain's Basque country where fish is cooked with the scales on. On the snapper here, they're combed back and fried crunchy, then plated with a fairly sweet purée of smoked potato, streaks of ink, a tangle of confit calamari threads, a couple of curls of seared calamari, and, for maximum cephalopod impact, a bubbly black piece of calamari crackling. It's striking, it's a smart mix of salt and sweet, and it perpetuates one of the great virtues of the kitchen: taking something ostensibly inedible and, by application of human cunning, transforming it into a delicacy.

Some of the best stuff is on the snacks menu. Take the long finger of crisply cut brioche, toasted evenly on each side, topped with a thin layer of crushed very ripe fig and then with a dusting of foie gras. The guys in the kitchen chill the foie just to the point where it's firm enough to Microplane, and the resulting shavings give you maximum foie flavour without too much ballast. It's there, and then it's gone. King seems to have a thing for big, dramatic shapes on the plate. Beyond the brioche number, there's the massive breadstick coated in cured Blackmore wagyu, pecorino, and squid ink breadcrumbs, served resting on a shiny tile propped up on a segment of polished marrow bone. &nbsp; Skeletal remains are also an accessory to the even more impressive tuna - good, fatty bits of belly meat served "yakitori-style" skewered on a knitting needle of tuna bone. The medium-rare fish is coated in smoked tuna jelly, and, matched with a quenelle of cucumber pickle and some sesame seeds, the overall effect is pretty dazzling. As "snacks", though, they're all pretty weird in that they're fairly pricy, sometimes tricky to eat and nearly all impossible to share. The puttanesca wafer, a crazy crisp mid-air scribble of olive, anchovy and parmesan, is among the most unwieldy of hors d'oeuvre ever to have graced a table. The solution to those sharing woes is quite simple: don't share.

Keep the duck to yourself, too. It's definitely one of the more bizarre pasta dishes you'll see this year: duck breast in neatly salted chunks, petals of pickled swede and a scattering of marigold around a pile of tagliatelle, duck ham, smoked duck tenderloin, slippery jacks and black trumpet mushrooms that's concealed under a veil of duck jelly. The touch that impresses me is that despite everything else going on here (and that's a lot), the tagliatelle hasn't been neglected. It's as well made as anything on the plate. It's a tremendously satisfying dish.

Things get wilder, if anything, with dessert: "nitro" pavlova made with whipped buttermilk, incorporating papaya, pineapple and coconut, for instance, or the liquid-centred orb of chocolate and honeycomb, god's gift to Cadbury Creme Egg lovers, with miniscule cookies-and-cream macarons as a garnish. This is not to say the kitchen is incapable of leaving well enough alone. The most interesting-sounding of the cheese courses is a whole Époisses, baked in its wooden box, and served molten, in all its washed-rind glory, for four, with a minimum of buggering around. It's an excuse to give the wine list a workout, too. This is a document that in most brasseries would look reasonably adventurous; in the context of Gastro Park it almost looks, dare I say it, too tame.

Out-there food is not easy to cook, but it's also demanding for the people serving it. In enlisting Martijn de Boer, a Pier alumnus, King has found a frontman who has the requisite professionalism and experience to know when to play it straight and when to go for laughs. And he knows his stuff, explaining even the most brain-teasing of King's creations with interest and understanding.

Grant King was doing very exciting food at Pier - at its peak his contribution, along with that of then-pastry chef Katrina Kanetani and owner Greg Doyle, saw it recognised as Gourmet Traveller's Restaurant of the Year. At Gastro Park, all the fine-dining trappings are gone, but the sense of adventure, the culinary bravado and the diamond-hard skills remain. It's not cheap, but you get more than you pay for. It's an exciting restaurant, and one we're lucky to have - and would smell as sweet by any other name.